1. Field
The present disclosure relates to a method for preparing a metal fluoride catalyst and dehydrofluorination method using the same. More particularly, the present disclosure relates to a method for preparing a metal fluoride catalyst, including reacting a chromium precursor as a metal precursor with a trifluoroacetic acid solution to form a chromium fluoride (Cr(NO3)3.9H2O) catalyst, and then reacting the resultant catalyst with 1,1,2,3,3,3-hexafluoropropane (also referred to as HFP-236ea hereinafter) to obtain 1,2,3,3,3-pentafluoropropene (also referred to as HFO-1225ye hereinafter), as well as to a dehydrofluorination method using the same.
2. Description of the Related Art
It is known that 1,1,1,2-tetrafluoroethane (also referred to as HFC-134a hereinafter) used as a refrigerant for cars is a greenhouse gas showing a global warming index up to 1300 times of the global warming index of carbon dioxide despite its high refrigerant characteristics.
Thus, EU prohibits the use of HFC-134a and regulates that a refrigerant for cars produced after 2011 cannot have a global warming index of 150 or higher. It is expected that such a regulation is extended to all cars in EU in 2017.
Under these circumstances, 2,3,3,3-tetrafluoropropene (also referred to as HFO-1234yf hereinafter) is a very suitable refrigerant and has a global warming index corresponding to about 4. It is also known that HFO-1234yf is produced by allowing the starting material, 1,1,2,3,3,3-hexafluoropropene (also referred to as HFP hereinafter) to pass through hydrogenation and dehydrofluorination alternately (U.S. Pat. No. 7,985,884 B2) (see the following Chemical Formula 1).

When preparing HFO-1234yf as shown in the above chemical formula, dehydrofluorination is essentially required as an intermediate process and a catalyst used for the dehydrofluorination according to the related art is a metal oxide catalyst treated with hydrofluoric acid (HF).
However, use of the HF-treated metal oxide catalyst entails such problems as corrosion of a reactor caused by HF during the preparation of catalyst, a decrease in active spots of a catalyst caused by treatment with HF, difficulty in forming a catalyst due to the use of HF, or the like.
Therefore, to solve the above-mentioned problems, the present inventors have found a method for preparing a metal fluoride catalyst as a substitute for the method for preparing a metal oxide catalyst including treatment with HF according to the related art, as well as a dehydrofluorination method using the same.